package desync

import (
	"context"
	"net"

	"github.com/rs/zerolog"
	"github.com/xvzc/SpoofDPI/internal/packet"
	"github.com/xvzc/SpoofDPI/internal/proto"
)

// TLSFake wraps another strategy to inject fake packets before the actual transmission.
type TLSFake struct {
	next           TLSDesyncer
	hopTracker     *packet.HopTracker
	packetInjector *packet.Injector
	windowSize     uint8
	count          uint8
	fakeMsg        *proto.TLSMessage
}

// NewTLSFake creates a decorator that sends fake packets before delegating to the next strategy.
func NewTLSFake(
	next TLSDesyncer,
	tracker *packet.HopTracker,
	injector *packet.Injector,
	windowSize uint8,
	count uint8,
	fakeMsg *proto.TLSMessage,
) TLSDesyncer {
	return &TLSFake{
		next:           next,
		hopTracker:     tracker,
		packetInjector: injector,
		windowSize:     windowSize,
		count:          count,
		fakeMsg:        fakeMsg,
	}
}

func (s *TLSFake) Send(
	ctx context.Context,
	logger zerolog.Logger,
	conn net.Conn,
	msg *proto.TLSMessage,
) (int, error) {
	err := s.sendFakePackets(ctx, logger, conn)
	if err != nil {
		logger.Error().Err(err).Msg("failed to send fake packets. skipping")
	}

	// Delegate to the wrapped strategy (e.g., ChunkStrategy or PlainStrategy)
	return s.next.Send(ctx, logger, conn, msg)
}

func (s *TLSFake) sendFakePackets(
	ctx context.Context,
	logger zerolog.Logger,
	conn net.Conn,
) error {
	src := conn.LocalAddr().(*net.TCPAddr)
	dst := conn.RemoteAddr().(*net.TCPAddr)
	ttl := s.hopTracker.GetOptimalTTL(dst.String())

	var fakeChunks [][]byte
	if s.windowSize > 0 {
		fakeChunks = split(s.fakeMsg.Raw, int(s.windowSize))
	} else {
		fakeChunks = [][]byte{s.fakeMsg.Raw}
	}

	var totalSent int
	for range s.count {
		for _, c := range fakeChunks {
			n, err := s.packetInjector.WriteCraftedPacket(ctx, src, dst, ttl, c)
			if err != nil {
				logger.Warn().Msg("failed to send fake packets")
				break
			}

			totalSent += n
		}
	}

	logger.Trace().
		Int("len", totalSent).
		Uint8("ttl", ttl).
		Msg("sent fake packets")

	return nil
}

func (s *TLSFake) String() string {
	return "fake+" + s.next.String()
}

// FakeClientHello is a pre-constructed Client Hello packet payload.
// This can be used for injection.
// Original code: https://github.com/ValdikSS/GoodbyeDPI/blob/master/src/fakepackets.c
var FakeClientHello = []byte{
	0x16, 0x03, 0x01, 0x02, 0x00, 0x01, 0x00, 0x01, 0xfc, 0x03, 0x03, 0x9a, 0x8f, 0xa7,
	0x6a, 0x5d, 0x57, 0xf3, 0x62, 0x19, 0xbe, 0x46, 0x82, 0x45, 0xe2, 0x59, 0x5c, 0xb4,
	0x48, 0x31, 0x12, 0x15, 0x14, 0x79, 0x2c, 0xaa, 0xcd, 0xea, 0xda, 0xf0, 0xe1, 0xfd,
	0xbb, 0x20, 0xf4, 0x83, 0x2a, 0x94, 0xf1, 0x48, 0x3b, 0x9d, 0xb6, 0x74, 0xba, 0x3c,
	0x81, 0x63, 0xbc, 0x18, 0xcc, 0x14, 0x45, 0x57, 0x6c, 0x80, 0xf9, 0x25, 0xcf, 0x9c,
	0x86, 0x60, 0x50, 0x31, 0x2e, 0xe9, 0x00, 0x22, 0x13, 0x01, 0x13, 0x03, 0x13, 0x02,
	0xc0, 0x2b, 0xc0, 0x2f, 0xcc, 0xa9, 0xcc, 0xa8, 0xc0, 0x2c, 0xc0, 0x30, 0xc0, 0x0a,
	0xc0, 0x09, 0xc0, 0x13, 0xc0, 0x14, 0x00, 0x33, 0x00, 0x39, 0x00, 0x2f, 0x00, 0x35,
	0x01, 0x00, 0x01, 0x91, 0x00, 0x00, 0x00, 0x0f, 0x00, 0x0d, 0x00, 0x00, 0x0a, 0x77,
	0x77, 0x77, 0x2e, 0x77, 0x33, 0x2e, 0x6f, 0x72, 0x67, 0x00, 0x17, 0x00, 0x00, 0xff,
	0x01, 0x00, 0x01, 0x00, 0x00, 0x0a, 0x00, 0x0e, 0x00, 0x0c, 0x00, 0x1d, 0x00, 0x17,
	0x00, 0x18, 0x00, 0x19, 0x01, 0x00, 0x01, 0x01, 0x00, 0x0b, 0x00, 0x02, 0x01, 0x00,
	0x00, 0x23, 0x00, 0x00, 0x00, 0x10, 0x00, 0x0e, 0x00, 0x0c, 0x02, 0x68, 0x32, 0x08,
	0x68, 0x74, 0x74, 0x70, 0x2f, 0x31, 0x2e, 0x31, 0x00, 0x05, 0x00, 0x05, 0x01, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x33, 0x00, 0x6b, 0x00, 0x69, 0x00, 0x1d, 0x00, 0x20, 0xb0,
	0xe4, 0xda, 0x34, 0xb4, 0x29, 0x8d, 0xd3, 0x5c, 0x70, 0xd3, 0xbe, 0xe8, 0xa7, 0x2a,
	0x6b, 0xe4, 0x11, 0x19, 0x8b, 0x18, 0x9d, 0x83, 0x9a, 0x49, 0x7c, 0x83, 0x7f, 0xa9,
	0x03, 0x8c, 0x3c, 0x00, 0x17, 0x00, 0x41, 0x04, 0x4c, 0x04, 0xa4, 0x71, 0x4c, 0x49,
	0x75, 0x55, 0xd1, 0x18, 0x1e, 0x22, 0x62, 0x19, 0x53, 0x00, 0xde, 0x74, 0x2f, 0xb3,
	0xde, 0x13, 0x54, 0xe6, 0x78, 0x07, 0x94, 0x55, 0x0e, 0xb2, 0x6c, 0xb0, 0x03, 0xee,
	0x79, 0xa9, 0x96, 0x1e, 0x0e, 0x98, 0x17, 0x78, 0x24, 0x44, 0x0c, 0x88, 0x80, 0x06,
	0x8b, 0xd4, 0x80, 0xbf, 0x67, 0x7c, 0x37, 0x6a, 0x5b, 0x46, 0x4c, 0xa7, 0x98, 0x6f,
	0xb9, 0x22, 0x00, 0x2b, 0x00, 0x09, 0x08, 0x03, 0x04, 0x03, 0x03, 0x03, 0x02, 0x03,
	0x01, 0x00, 0x0d, 0x00, 0x18, 0x00, 0x16, 0x04, 0x03, 0x05, 0x03, 0x06, 0x03, 0x08,
	0x04, 0x08, 0x05, 0x08, 0x06, 0x04, 0x01, 0x05, 0x01, 0x06, 0x01, 0x02, 0x03, 0x02,
	0x01, 0x00, 0x2d, 0x00, 0x02, 0x01, 0x01, 0x00, 0x1c, 0x00, 0x02, 0x40, 0x01, 0x00,
	0x15, 0x00, 0x96, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
}
